The present invention relates to a cutting plotter for cutting a sheet-like cutting target.
A cutting plotter for cutting a sheet-like cutting target by moving the cutting target and a cutter is called a grit rolling type cutting plotter. As disclosed in Japanese Patent Laid-Open No. 2003-305688 (literature 1) and Japanese Patent Laid-Open No. 2005-205539 (literature 2), a cutting plotter of this kind includes a pair of rollers for clamping a cutting target. The pair of rollers include a driving roller which is rotated by a driving device, and pinch rollers for clamping a cutting target by cooperating with the driving roller.
The driving roller rotates forward or backward when driven by the driving device. For example, a cutting target moves forward when the driving roller rotates forward, and moves backward when the driving roller rotates backward. The cutter moves in a vertical direction perpendicular to the major surface of the cutting target, and in a horizontal direction perpendicular to a forward-backward direction as the moving direction of the cutting target. The cutter sticks in the cutting target when moved downward and pressed to the cutting target. The cutting target is cut into a predetermined shape by moving the cutter in the horizontal direction and moving the cutting target in the back-and-forth direction while the cutter is stuck in the cutting target.
The above-described pinch rollers are arranged in positions corresponding to at least the two end portions of the cutting target. A press roller for pressing a middle portion of the cutting target is formed between the pinch rollers. The middle portion of the cutting target is pressed mainly because of the following two reasons. The first reason is to place the cutting target along the driving roller so that the cutter can correctly cut the cutting target in a cutting process. The second reason is to prevent the cutting target from being pulled and lifted by the cutter when the cutter rises after cutting. The press roller is formed by rubber.
As disclosed in Japanese Patent Laid-Open No. 08-072489 (literature 3), a large-sized cutting plotter sometimes includes a pressing mechanism for supporting the press roller. This pressing mechanism includes a swing arm having a swing end portion to which the press roller is rotatably attached, and a spring member for biasing this swing arm in a direction in which the press roller is pressed against the cutting target.
The cutting plotter including the rubber press roller poses a problem when cutting a relatively thick object as the cutting target. Examples of the relatively thick cutting target are a flute material and embossed sheet. When a thick cutting target like this is passed between the press roller and driving roller, the press roller is strongly pressed against the cutting target, and a recessed groove is formed on the cutting target. When the press roller is formed by black rubber, a black linear mark remains on the surface of the cutting target against which the press roller is pressed.
This inconvenience can be eliminated to some extent by adopting the arrangement in which the press roller is supported by the swing arm and pressed against the cutting target by the spring force of the spring member. However, the manufacturing cost increases if this arrangement using the swing arm is adopted.